This invention relates to hydroalkylation. More specifically it relates to a method of increasing the activity of a catalyst which may be used in the hydroalkylation of benzene to form cyclohexylbenzene at high productivity.
As is well known to those skilled in the art, catalysts may be used in a wide variety of processes including hydroalkylation, disproportionation, transalkylation, isomerization, cracking, reforming, hydrodewaxing etc. Typical of such catalysts may be those containing a support on which is deposited an active component.
In the case of hydroalkylation catalysts, they are commonly dual site catalysts providing for centers of hydrogenation activity and for centers of alkylation activity. Typically such catalysts may contain a support such as silica-alumina or zeolite on which is mounted on active metal, typically a Group VIII metal.
Efficient operation requires that the catalyst possess as high a degree of activity as is possible; and to this end various pretreatment processes have been employed. Various techniques may include calcining at temperatures up to 1700.degree.F. for times up to 8 hours followed by reduction at temperatures to 750.degree.F. for times up to 2 hours or to higher temperatures of eg 1000.degree.F. for one hour.
The degree of activation achieved by such techniques has heretofore been less than desired; and it has frequently been found that the improvement is not obtained at a cost which renders the treatment economical.
It is an object of this invention to provide a method of increasing the activity of a catalyst. It is another object of this invention to provide a method of hydroalkylation. Other objects will be apparent to those skilled in the art.